Various wishes

The visuals for the all the analog modes are achieved by sampling the inputs with the CS4231A. The SAA7705H is still responsible for the audible path.

Although rumors have it that there is an additional source now which I guess might come from the CS4231A. In principle it would be possible to sample the radio via the CS4231A and pump the samples back out through the SAA7705H. In practice, the sample rate is differerent and limited, so it would be difficult to implement and result in lessor quality radio. Not only that but quite a bit of kernel code makes decisions based upon which of the 4 SAA inputs is in use, so you could expect stuff to break.

Not going to happen.

Hmm. That hadn't occurred to me at all since we don't have that concept in the US. (Even though the same three companies own like 95% of the radio stations, they do manage to at least not have all of their stations playing the exact same thing. At least not at the same moment.)

No, you didn't understand what Peter was saying. He wasn't suggesting that BBC Radio 1 and BBC Radio 2 would be playing the same thing!

Radio is very different between the USA and most of Europe. In the USA most channels are broadcast with a gazillion Watts from one transmitter only. If you're in the reception area, great, if not. tough.

In the UK, many channels are broadcast nationally from many transmitters with less power. So when you travel west from Sheffield and cross the Pennines, and you lose reception from the Pontop Pike transmitter, you should pick up reception from a transmitter on the western side of the Pennines (Sanfield). Obviously reception isn't a yes/no affair - there is a zone that you will receive both signals.
If those two transmitters broadcast on the sam frequency then this would be a problem. Even if the two transmitters are frequency- and phase- locked together, as soon as you move the receiver the Doppler Effect comes into play, raising the perceived frequency of the transmitter that you are travelling toward and lowering the other. This results in 'beating' where the reception fades in and out rapidly.

To get around this, different transmitters broadcast the same program on different frequencies, so when reception from the Pentop Poke transmitter deterioates too much, you try the frequency of the Sanfield transmitter to see if the reception is better. (This is one of the things that RDS does automatically.)

So the bank concept probably originated in being able to keep two sets of frequencies for each channel, and easily being able to switch between them to change which transmitters you were listening to.

HTH.

No. I understood that completely. Thanks for the reiteration, though.

When driving to Atlanta from Raleigh a few months back I listened to three rock clear channel stations playing the same hourly song list exactly one hour apart. It was strange to listen to a raleigh staton for an hour, lose signal, find charlotte station playing the same set list, lose channel, listen to a atlanta station playing same list, I switched to 'clear channel' country instead...

No I had no empeg with me and I did not have my karma yet.


Sean in NC

Doh, I misinterpreted your post. There goes another 10 minutes that I'll never get back.

Another wish I'd like for the time alignment is ......
Instead of delaying the whole frequency spectrum have it broken into 2 groups.
For instance from 80 to 3000 Hz for mids and 3000 up for tweeters.
I have tweeters in the dash and mids down low in the doors so the distance from the left tweeter to my ears and the right tweeter and my ears is different than the left mids and my ears and the right mids and my ears.
If I set up the delay so the mids sound correct the tweeters sound off and visa versa.

see the crude attachment for example

Yeah, that would be useful. although it would be _incredibly_ hard if not impossible to implement. The existing delay simply (!) delays all the samples which is computationally cheap. To split different frequencies would require that the kernel implement a software crossover, which would be computationally expensive.

Align on your tweeters as high frequency is far more directional. You might want to notch the bass up to account for the phase error from the mids.